Clinical significance of sleep-disordered breathing induced by sedatives during ablation of atrial fibrillation

Clinical usefulness of the body muscle-to-fat ratio for screening obstructive sleep apnea syndrome in patients with inadequately controlled type 2 diabetes mellitus

AIMS

To investigate whether body composition measures can be used for screening obstructive sleep apnea syndrome (OSAS) in patients with type 2 diabetes mellitus (T2DM) suspected of having OSAS.

METHODS

Subjects were 186 hospital inpatients with inadequately controlled T2DM. We measured the respiratory disturbance index (RDI) as an indicator of OSAS using a sheet-type breath detection monitor, defining OSAS as an RDI ≥ 19 events/hour. Elementary body composition was measured by bioelectrical impedance analysis using InBody770.

RESULTS

Simple logistic regression analysis identified body weight, body mass index (BMI), waist circumference, total body fat mass, body fat percentage, and body muscle-to-fat ratio (BMFR) as significantly associated with OSAS. The Nagelkerke R² test showed that the BMFR was the most suitable measure for screening OSAS. Multivariate logistic regression analysis demonstrated that BMFR was significantly and independently associated with OSAS. In receiver operating characteristic curve analysis, the area under the BMFR curve was 0.70 (P < 0.001), indicating that BMFR was significantly predictive of OSAS. Furthermore, BMFR was the most suitable measure for screening OSAS in a sub-group analysis of non-obese patients with relatively low BMI (<27.5 kg/m²).

CONCLUSIONS

In patients with T2DM, the BMFR is useful for screening OSAS in daily clinical practice.

Relationship between sleep-disordered breathing and renal dysfunction in acute coronary syndrome

BACKGROUND

Sleep-disordered breathing (SDB) is associated with cardiovascular complications. However, the effect of SDB on renal function in patients with acute coronary syndrome (ACS) treated by percutaneous coronary intervention (PCI) remains unclear.

METHODS

We enrolled 154 consecutive ACS patients without heart failure. A sleep study was performed immediately after PCI.

RESULTS

The mean apnea-hypopnea index (AHI) was 16.4±13.1, and 33 patients (21%) had severe SDB, defined as AHI≥25. Estimated glomerular filtration rate (eGFR) values on admission (60±12mL/min/1.73m² vs. 67±17mL/min/1.73m², p=0.046) and at discharge (54±15mL/min/1.73m² vs. 63±15mL/min/1.73m², p=0.002) were lower in patients with severe SDB than in those patients without severe SDB. Multiple linear regression analysis showed that AHIs were significantly correlated with absolute changes in eGFR values from admission to discharge (β=0.201, p=0.004). Median 24-h urinary noradrenaline excretion measured on the same day of the sleep study was higher [297 (interquartile range {IQR}: 232-472) vs. 174 (IQR: 107-318)μg/day, p=0.021] in patients with severe SDB. On multivariate logistic regression analysis, the presence of severe SDB was a significant predictor (adjusted odds ratio 3.76, 95% confidence interval 1.06-13.9, p=0.047) for eGFR of less than 45mL/min/1.73m² at discharge. This association was independent of age, eGFR on admission, and a presentation of ST-segment elevation myocardial infarction.

CONCLUSION

In patients with ACS who undergo PCI, severe SDB is associated with impaired renal function on admission and its deterioration during hospitalization. Further studies will be needed to conclude that SDB would be a therapeutic target in ACS.

Plasma brain-derived neurotrophic factor and reverse dipping pattern of nocturnal blood pressure in patients with cardiovascular risk factors

CONTEXT

Basic studies have shown that brain-derived neurotrophic factor (BDNF) has critical roles in the survival, growth, maintenance, and death of central and peripheral neurons, while it is also involved in regulation of the autonomic nervous system. Furthermore, recent clinical studies have suggested potential role of plasma BDNF in the circulatory system.

OBJECTIVE

We investigated the mutual relationships among plasma BDNF, patterns of nocturnal blood pressure changes (dippers, non-dippers, extra-dippers, and reverse-dippers), and cardiac autonomic function as determined by heart rate variability (HRV).

DESIGN

This was a cross-sectional study of patients registered in the Hyogo Sleep Cardio-Autonomic Atherosclerosis (HSCAA) Study from October 2010 to November 2012.

PATIENTS

Two-hundred fifty patients with 1 or more cardiovascular risk factor(s) (obesity, smoking, presence of cardiovascular event history, hypertension, dyslipidemia, diabetes mellitus, chronic kidney disease) were enrolled.

RESULTS

Plasma BDNF levels (natural logarithm transformed) were significantly (p = 0.001) lower in reverse-dipper patients (7.18±0.69 pg/ml, mean ± SD, n = 36) as compared to dippers (7.86±0.86 pg/ml, n = 100). Multiple logistic regression analysis showed that BDNF (odds ratios: 0.417, 95% confidence interval: 0.228-0.762, P = 0.004) was the sole factor significantly and independently associated with the reverse-dippers as compared with dippers. Furthermore, plasma BDNF level was significantly and positively correlated with the time-domain (SDNN, SDANN5, CVRR) and frequency-domain (LF) of HRV parameters. Finally, multiple logistic regression analyses showed that the relationship between plasma BDNF and the reverse-dippers was weakened, yet remained significant or borderline significant even after adjusting for HRV parameters.

CONCLUSIONS

Low plasma BDNF was independently associated with patients showing a reverse-dipper pattern of nocturnal blood pressure, in which an imbalance of cardiac autonomic function may be partly involved.